1. Field of the Invention
The present invention relates to a method of manufacturing a master recording medium, a magnetic transfer method using the manufactured master recording medium, and a method of manufacturing a magnetic recording medium, and particularly relates to a method of manufacturing a master recording medium with an excellent exfoliating property and low manufacturing cost, a magnetic transfer method using the manufactured master recording medium, and a method of manufacturing a magnetic recording medium.
2. Description of the Related Art
As recording media, magnetic recording media typified by a hard disk are available. A high density and high-speed processing of information are increasingly demanded of such magnetic recording media and high-density magnetic recording media are desired which can record a large amount of information with a large capacity, enable low cost, and preferably enable reading of a desired part in a short time, that is, high-speed access. In such a high-density magnetic recording medium, an information recording area is made up of narrow tracks. In order to cause a magnetic head to accurately scan with a small track width to reproduce a signal with a high signal-to-noise ratio, a so-called tracking servo technique plays a significant role. A sector servo system is widely used to perform the tracking servo technique.
In the sector servo system, servo information including a servo signal for positioning a track, an address information signal of the track, and a reproduction clock signal is recorded in servo fields correctly arranged with a fixed angle and the like on a data surface of a magnetic recording medium such as a magnetic disk, and a magnetic head scans the servo fields to read the servo information and corrects the position of the head while locating the head.
It is necessary to record the servo information as a preformat beforehand on a magnetic recording medium during the manufacturing of the magnetic recording medium, and preformatting is currently performed using a dedicated servo recorder. A currently used servo recorder has, for example, a magnetic head having a head width about 75% of a track pitch. A magnetic disk is rotated in a state in which the magnetic head is disposed close to the magnetic disk; meanwhile a servo signal is recorded for each half track while the magnetic head is moved from the outer edge to the inner edge of the magnetic disk. Thus it takes a long time to perform preformat recording on a magnetic disk, resulting in low production efficiency and increase in cost.
Thus as an accurate and efficient method of preformatting, a method of magnetically transferring information on a master recording medium to a magnetic recording medium is disclosed. A pattern corresponding to servo information is formed on the master recording medium.
In such magnetic transfer, a master recording medium is used which has a transfer pattern including a concavo-convex pattern according to information to be transferred to a magnetic recording medium (slave medium) such as a transfer magnetic disk, and a magnetic field for recording is applied in a state in which the master recording medium and the magnetic recording medium are in contact with each other, so that a magnetic pattern corresponding to information (for example, servo information) recorded with the concavo-convex pattern of the master recording medium is magnetically transferred to the magnetic recording medium. In this method, recording can be statically performed without changing the relative positions of the master recording medium and the magnetic recording medium, preformat information can be accurately recorded, and quite a short recording time can be achieved. Two magnetic transfer methods are available which include perpendicular magnetic recording for recording magnetization information to be transferred to a magnetic recording medium by perpendicular magnetization and in-plane magnetic recording for recording magnetization information by in-plane magnetization parallel to a magnetic recording medium.
In order to perform such magnetic transfer, a master recording medium is used which is a master disk having a concavo-convex pattern formed thereon. Japanese Patent Application Laid-Open No. 2004-265558 and Japanese Patent Application Laid-Open No. 2006-59597 disclose the method of manufacturing the master recording medium. A high density is also increasingly demanded of such a magnetic recording medium typified by a hard disk. The larger the recording capacity, the smaller the concavo-convex pattern formed on the master recording medium.